As Russia and the US sign a deal bringing swinging cuts to nuclear arsenals, BBC News Online asks whether history has been made.

How important is this deal?

The reason that both the US and Russia are prepared to get rid of so many warheads is partly a sign of the good relations that now exist between the two countries - but also reflects the fact that neither country now measures its security in terms of nuclear stockpiles.

The world has moved on since the 1980s, when the superpower relationship seemed like the key to everything.

Russia is no longer a superpower. It cannot afford to replace ageing warheads, and even maintaining the stockpile at its current size is a major strain on resources.

For purely economic reasons Moscow had to reduce its arsenal. Now it has persuaded Washington to do the same.

Much more important for world security is the evolving relationship between Nato and Russia.

If their plans for partnership become a reality, this will represent a far bigger step forward.

Is the Cold War now history?

George Bush has often reminded the world that the Cold War is over.

Last year - before 11 September - he cited this as a reason why Russia should enter into a new, warmer relationship with the US.

Later he went on to argue that since the US and Russia were no longer adversaries, there was no need for them to formalise these latest nuclear cuts in the shape of a treaty - but Russia insisted.

In reality, the Cold War ended long ago, during the presidency of George Bush senior, which lasted from 1989 to 1993.

However, even today Cold War thinking persists in both the US and Russia, particularly among the military.

Liquidating warheads rids the world of one kind of Cold War legacy, but anachronistic attitudes are harder to root out.

Is the world now a safer place?

It can take a long time for arms cuts, agreed in principle, to be carried out in practice.

It took Russia seven years to ratify the Start II nuclear reduction treaty, designed to leave each country with no more than 3,500 warheads.

Supposing these latest cuts are eventually made, each side will still have in the region of 2,000 warheads - a massive destructive force.

Analysts say that despite the deal, Russia still poses a long-term proliferation threat. Some of the warheads will not be destroyed, just stored, in case they are needed again.

But, as warheads are decommissioned the nuclear materials they contain must be securely stored to prevent them getting into the wrong hands.

Security at some vulnerable nuclear sites is poor and there are significant fears that terror suspects or "rogue states" could steal or buy nuclear weapons or weapons-usable materials.

The International Atomic Energy Authority says it has traced incidents of illicit trafficking in nuclear material that originated in Russia and former Soviet Union nations.

Is the US set to dominate Russia indefinitely?

Russia is beginning to recover economically, after hitting rock bottom in the 1990s.

Politically, it has a greater sense of direction under President Vladimir Putin.

But militarily and technologically, it has a long way to go.

Reforming the military has long been among the Kremlin's priorities.

But there are entrenched interests and the military bureaucracy is resisting change. While soldier numbers have been reduced, little else has yet been achieved.

It will be decades at least before Russia can match current US military spending.

By that time China is likely to be challenging the US as the world's emerging superpower.

What does Russia think of the deal?

Some Russian commentators regard the US's refusal to destroy all warheads taken out of service as a defeat for Moscow.

However, for Russian conservatives it is the unspoken quid pro quo - Moscow's acquiescence to US missile defence plans - that will stick most firmly in the gullet.

Nato's likely expansion later this year into the Baltic states will also make big waves.

Altogether, with the US military's arrival in Central Asia and the Caucasus (post 11 September) Russian hawks have been having a hard time recently.

Realists are likely to accept that Russia played a weak hand well, and has got the best possible deal under the circumstances.